Patent GB-1413540-A (GB)
Title: Method and apparatus for depositing wire on a thermoplastic sheet
IPC: B29C70/82
Filed: 1972-11-27
Abstract: 1413540 Laminates SAINT GOBAIN INDUSTRIES 27 Nov 1972 [29 Nov 1971 (2) 3 Feb 1972] 54679/72 Heading B5N [Also in Division H5] A method of depositing one or more wires on a thermoplastic sheet, e.g. polyvinyl butyral, for use as the intermediate layer of a laminate, e.g. an electrically heatable glass laminate wherein the or each wire is deposited in a predetermined non-linear pattern, the method comprising the steps of giving the or each wire the shape required to form the pattern by a pair of shaping members adjacent the sheet and depositing the or each wire on the sheet in a stress-free condition by pressing means intermediate the shaping members. In effecting the method, the sheet may be plasticized by the action of heat before the deposition of the wire(s) optionally by heating the shaping and pressing device. Alternatively, the sheet may be plasticized by the action of a solvent for the sheet. An adhesive may be used for bonding the wire(s) to the sheet. An apparatus for effecting the method of the invention comprises a support 5 for the thermoplastic sheet, a pair of shaping members for the or each wire arranged above the support to guide the wire and provide it with the required shape, and pressing means intermediate the shaping members movable to press the shaped wire against the sheet. In the embodiment shown in Figs. 1 and 2, the apparatus comprises a rigid frame consisting of a series of parallel rails 25 having deforming wedges 26 and 27 directed laterally towards each other and having chamfered surfaces mounted thereon, the wedges 26 fitting into the gaps between the wedges 27, each wedge 26 being spaced slightly from the corresponding wedge 27 so that a vertically moving pressing finger 30 may be introduced into each gap, the wire 31 being laid between the rails 25 so that it lies on the chamfered surfaces of the wedges 26, 27. In operation, the pressing fingers 30 are lowered sequentially, the fingers being preferably heated to fix the wire to the sheet 32. In the embodiment of Fig. 7, the frame which is layed on sheet 65 lying on a table 66 consists of a rail 62 having deforming wedges 63 and 64 fixed thereto, the pressing fingers 68 for applying the wire 67 to the sheet 65 being arranged as radial projections at the periphery of a roller 69. In the embodiment of Fig. 8, the deforming wedges 70, 71 are arranged at the peripheries of circular rings 73 in such a manner that they mesh into one another, pressing wheels 77 being arranged between the rings 73 and having over their whole peripheries radially extending pressing fingers which fit into the spaces between the wedges 70 and 71. In the embodiment of Figs. 12 and 13, the deforming wedges for the wire are provided at the periphery of guide rings 94 in the form of thin discs of spring steel, the radial projections 95 on one guide-ring being spaced such that the projections 95a of the adjacent guide and the pressing fingers 96 can fit therebetween, discs 98 being arranged between the guide rings 94 to serve as bearings for the pressing rings 99, the radial projections of each guide ring being displaced by spreading ring 100. In the embodiment shown in Fig. 14, the wire is guided on the periphery of the wire applying roller, the applying device comprising two obliquely arranged guide rings 110 each provided at its periphery with teeth 111 directed towards the corresponding teeth of the other ring, pressing fingers 113 arranged on pressing ring 112 fitting between the teeth. Fig. 24 shows a complete machine for applying a plurality of wires to a thermoplastic sheet, 150, the machine comprising a frame carrying a support roller 154 for the sheet and two idler rollers 155, 156, conductors 160 consisting of thin metal foils or metal flex being applied to the sheet prior to introduction into the machine to serve as current supply means for the wires, an electrically heated support shaft 163 carrying wire supply bobbins 165 and wire deforming devices 166 being arranged above the roller 154.